Rear End Banging Noise

[CAR3NUT]

Ever since I got 673 there has been a banging noise coming from the rear of the car when going over the reflectors on the highway and/or over certain joints in streets.
SC center is was the ball joints so they ordered two. Had them replaced, but the noise is still there. In my research I see there two ball joints per wheel. Question is, do I need to replace all 8 or is there something else going on? Would a bad shock create this noise? It almost sounds like someone taking a hammer and hitting metal!

 

[jason.tv]

if you don't have the sport adjustable suspensions this seems like it's normal. Maybe a shock is going bad, how many miles on the car? Is it both rear wheels or just one of the left or right rear ones?

 

[CAR3NUT]

50,000 miles, sounds mostly the rear, yet my mech thought it might also be the fronts. Was going to order the of set (8) from Lotus and have mech replace all 8. then maybe move onto the rear shocks, which are not leaking.

 

[jason.tv]

I don't think the joints are going to help; My lotus guy said the joints are overkill for the car and not needed; considering you feel the same in the fronts, If your car rides firm, stiff, hard, or just not comfortable then it's definitely the non sport suspensions giving you one type of ride feel.

 

[CAR3NUT]

The ride I don't think is what I would consider stiff because driving on normal roads with a few dips and humps the suspension is really pretty smooth. It is when you hit highway reflector markers when you change lanes and/or large cracks in the roads that the noise appears. The SC when they test drove the car said it was the rear ball joints. Not a mechanic so not sure where the issue is, but I don't think it is normal.

 

[gregd]

Hard to know without hearing your car, but it seems like the same sound I've noticed with mine. My solution is to treat the reflectors as a "lane departure warning", and try not to hit them. I think it's just the sudden mechanical shock that is transmitted to the car, and we're hearing the body panels flex and vibrate.

 

[JohnGarziglia]

Ever since I got 673 there has been a banging noise coming from the rear of the car when going over the reflectors on the highway and/or over certain joints in streets.

The noise you describe is more or less normal depending upon the size of the bumps you are going over. But, there are things that could be unassociated with the rear suspension that you should also check as sometimes it is difficult to discern exactly where a noise is coming from. The rear suspension will never be Lexus quiet, but there are a number of other things that can amplify and enhance rear suspension noise.

The simplest thing is to make sure nothing is in the trunk that is bouncing around. Make sure there are no loose tools under the the trunk floor. I have the Tesla J1772 adaptor cord and just that in the trunk being in a bag with the two heavy metal sockets banging together caused a similar noise -- I fixed that noise by using two beer can holders (the foam kind) over both ends. Also check the metal pan beneath the engine and battery. If not screwed in tightly, that could make a similar noise. I put Dynamat on that metal pan as well as on the side carbon fiber panels in the rear. I have documented elsewhere on this forum where both the emergency lock brackets in my driver's door, and the window rail in the passenger's door, became unglued and were prone to banging around over bumps.

 

[CAR3NUT]

The noise you describe is more or less normal depending upon the size of the bumps you are going over. But, there are things that could be unassociated with the rear suspension that you should also check as sometimes it is difficult to discern exactly where a noise is coming from. The rear suspension will never be Lexus quiet, but there are a number of other things that can amplify and enhance rear suspension noise.

The simplest thing is to make sure nothing is in the trunk that is bouncing around. Make sure there are no loose tools under the the trunk floor. I have the Tesla J1772 adaptor cord and just that in the trunk being in a bag with the two heavy metal sockets banging together caused a similar noise -- I fixed that noise by using two beer can holders (the foam kind) over both ends. Also check the metal pan beneath the engine and battery. If not screwed in tightly, that could make a similar noise. I put Dynamat on that metal pan as well as on the side carbon fiber panels in the rear. I have documented elsewhere on this forum where both the emergency lock brackets in my driver's door, and the window rail in the passenger's door, became unglued and were prone to banging around over bumps.

I don't carry anything in the trunk other than the tool kit which is in original bag. I have gone through and tightened every bolt I could get access to thinking that maybe one or two was loose. The PO had the battery replaced in 2015 with a re-manufactured battery and I was wondering if that could be an issue with it not being bolted to the frame correctly? There are so many variables to this issue. Guess I will look up your thread on the driver's door lock brackets.

 

[JohnGarziglia]

...Guess I will look up your thread on the driver's door lock brackets.

This is the thread on the driver's door lock brackets: Emergency Lock Bracket Disconnected